The present invention relates to vertical take-off and landing (VTOL) aircraft and more specifically to a tactical VTOL aircraft adapted for covert deployment and low vulnerability to hostile detection and assault.
Tactical vertical takeoff and landing (VTOL) aircraft are known. Such known tactical VTOL aircraft are generally quick and maneuverable rotary blade aircraft, i.e. helicopters, that are used for airborne special operations. Being small-and relatively quiet, and having a sufficient load to size ratio, these VTOL aircraft have provided a stable platform for the special operations world. They are sufficiently suited for providing a xe2x80x98ride to targetxe2x80x99 and air support for ground troops. Technical evolution of such known VTOL aircraft has resulted in VTOL aircraft that can be used for xe2x80x98fast-ropexe2x80x99 insertions and/or be outfitted with weapons such as mini 0.50 caliber machine guns, missiles, grenade launchers and aerial rockets. However, known tactical VTOL aircraft are still range/payload constrained and need to be flown with hostile ground fire, ever maturing radar, infrared and acoustic based threats in mind.
A variety of methods have been employed to provide vertical takeoff capability. These methods include providing ducts to redirect the discharge from a main propulsion unit, providing a tilt mechanism to permit main engine(s) to tilt, and providing separate engines for driving fan systems to lift the aircraft. Aircraft range and payload capabilities are reduced when weight and structural changes required to incorporate vertical takeoff capabilities are incorporated into an aircraft. For example, oversized axial propulsion will reduce cruise efficiency. The complexity of an aircraft designed to accommodate both horizontal and VTOL capabilities also increases the maintenance requirements on the aircraft and therefore increases the overall life cycle costs to operate the aircraft.
Additionally, known VTOL aircraft must still be operated in view of increasingly dangerous risks. For example, detection/observation methods such as radar, infrared, acoustical, electromagnetic, contrails and visual detection pose serious survivability threats to known VTOL aircraft. Acoustically, the rotors of typical VTOL aircraft generate a strong, broadband signature that is very distinctive making them very vulnerable to acoustical detection. Untreated engine exhaust create an easy target for shoulder launched heat seeking missiles and very little radar cross section detection is possible. The maturation of detection sensors and antiaircraft weapons has progressed to a point that aircrews and passengers are at an ever increasing risk.
A need therefore exists for a VTOL aircraft with the characteristics of affordability, enhanced range/payload, high speed, and low vulnerability to hostile detection and threats.
According to one preferred embodiment, an aircraft adapted for covert deployment and having low vulnerability to hostile detection and aggression is provided. The aircraft includes a fuselage having a pair of sidewalls and a bottom. The sidewalls and bottom form an armored payload bay. The aircraft additionally includes a pair of wings connected to the fuselage. The wings have a fixed wingspan constrained such that the aircraft can be transported within a larger aircraft. This allows for the aircraft to be aerial deployed from the larger aircraft. Each of the sidewalls include at least one pulse ejector thrust augmentor (PETA) bank that is canted outward. Therefore, thrust exhaust produced by each PETA bank is directed down and away from a centerline of the payload bay. Furthermore, the bottom of the aircraft is adapted to allow ingress and egress of cargo, e.g. military troops, from the payload bay.
According to another preferred embodiment, a method for enhancing protection of an aircraft against hostile detection and aggression is provided. The method includes constructing a pair of fixed wings of the aircraft to have a wingspan that allows the aircraft to be transported within, and deployed from, a larger airborne aircraft. The method additionally includes providing an armored payload bay within a fuselage of the aircraft. The payload bay has a pair of armored walls adapted to protect an interior area of the payload bay from infiltration by flying objects. The method further includes disposing at least one pulse ejector thrust augmentor (PETA) bank within each sidewall. At least a portion of the protection provided by the payload bay armored walls is the result of the thickness of the PETA bank in each sidewall. The payload bay additionally has an armored bottom adapted to allow ingress and egress of cargo from the payload bay. Each PETA bank is canted outward such that a thrust exhaust produced by each bank is directed down and away from a centerline of the payload pay. Further yet, the method includes canting an exterior surface of each sidewall to reduce radar cross section returns reflected from the fuselage of the aircraft.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the Invention.